You can’t use length as a judge of bore. Older 122mm guns and 105mm even more modern types are actually pretty close in size. This is as they occupy a similar mission role of field artillery. With similar range and employment strategy. When vehicle mounted they can even mount on the same host. Example the Chinese SH2 and SH5 used the same host vehicle and are all but identical in photos. But one the 2 is a 122mm well the other is a 105mm.sure it's a 122mm??? Judging by the size of the gun, single rear axle vehicle, size & number of rounds carried i am inclined to believing this is a 105mm mount.
Most likely true. Wouldn't have so many people paying attention to it if it wasn't. It's too niche a thing to be made up and corruption in Chinese leadership and industry is almost cultural. Things like this is why the Japanese used obsolete Japanese vessels to sink the Chinese navy using the latest and greatest imported German ones of that time, pre-WW2 Sino Japanese war. The corrupt Chinese commanders sold the guns off to pay off gambling debts.