I have been to HP, and I don't think the halls are big enough to house 055s (23 meters wide).
If the 055 Block IIs are equipped with electromagnetic rail guns, would the 055s be similar to the DDG-1000?
DDG-1000 class is in a class of its own. It uses a number of new technologies and has the capability to field some more (such as rail guns and DEW due to its IEPS). But DDG-1000 class also has a very strange armament mix and thus it has a very strange role... because for a 15,000 ton ship it "only" has 80 VLS, while it carries two large 155mm advanced gun systems. It also heavily emphasizes stealth. It is also equipped with no real ciws, only having two 30mm guns more suited to anti surface point defence than shooting down AShMs.
Even if DDG-1000 replaces its two 155mm guns with rail guns in future and if they supplement their 30mm guns with DEW laser ciws, the ship is still a bit of a strange animal. The immense attention and money paid to its stealth means it basically is not going to be actively emitting and will exercise EMCON to preserve its stealth. In fact, DDG-1000 doesn't even have an S band MFR and has to rely on an X band MFR for volume search as well as horizon and surface search. This basically means DDG-1000 isn't going to be part of any carrier battle group as part of an escort, and will likely be used as a "strike cruiser" where it may carry a large load of LACMs or ASHMs in its 80 VLS rather than SAMs (though Mk-57 PVLS no doubt can carry the ESSM and standard missile family). But only 3 DDG-1000 class ships will be built, meaning their availability will also be quite limited during standard operations. The game changing nature of railguns in many future high intensity combat scenarios is also not entirely certain, because while they will obviously revolutionize the capability of a ship's main gun and possibly ciws, even optimistic projections do not see them having a range that can truly replace LACMs which can have range in excess of 1500km, meaning if one wants to attack land targets with shipboard railguns they may have to get within 200nm of the target.... and if one is facing a capable high tech enemy, one has to ask whether you want to send a multibillion dollar warship that close simply to use your rail guns. Of course, one can still park DDG-1000s 1000km from a target and lob cruise missiles away, but one can do that with a Burke as well.
Therefore, I'd argue that despite the DDG-1000's impressive array of new technologies and design, and its potential for fielding railguns and DEWs, it is also a ship only in limited numbers and in many ways it is searching for a mission. (Though obviously other missions where DDG-1000 may excel at is as a command ship)
055 on the other hand, is thought to have 112 or 128 VLS, and likely displaces quite a bit less possibly at 13,500 ton full displacement. It also will likely be equipped with three advanced active radars, which strongly suggests it will actively emit during many missions, i.e.: it will act as an air defence ship. A 130mm main gun and a PJ-11 30mm CIWS and a 24 cell HQ-10 CIWS SAM rounds off the 055's armament and makes the ship look like an upsized ticonderoga or Sejong class in terms of role and armament, only carrying more and newer radars, and being bigger, and being stealthier as well (though 055 will not be as stealthy as DDG-1000 class -- and it is not meant to be given its mission will mean it will actively emit often and thus possibly give away its position, reducing the effectiveness of the stealth that DDG-1000 class may have given the cost of such stealth).
But 055 is also large enough to accommodate newer propulsion. 055 is expected to use four QC-280 gas turbines in COGAG arrangement, but it is also expected that an eventual 055A will field IEPS, possibly using the same four QC-280 gas turbines. that would likely give 055A enough electricity to power newer and more powerful radars, but also more importantly to power a railgun (to replace the PJ-38 130mm main gun) and equip itself with DEW lasers. However it is unlikely that 055A will reduce the number of VLS, and it will also likely retain its current CIWS in addition to any laser CIWS. 055A may be more stealthy relative to 055, but I cannot see any reason for the Chinese Navy to seek stealth on the scale of DDG-1000 class.
So in short, to answer your question, if 055A does get IEPS and is equipped with a railgun, it would still likely be quite different to the Zumwalt class as it currently is and also quite different to the Zumwalt class if it were refitted with railguns... because there are many unique aspects of the Zumwalt class and its sensor suite, armament choice and count, and overall design (namely for the sake of stealth), which 055 and 055A likely will not replicate.