It’s all very mysterious.
My most stalwart sources, Zaloga and Grandsen’s “Soviet Tanks and Combat Vehicles of WW2” and Karpenko’s “Obozrenie otechestvennoi bronetankovoi tehniki, 1905-1995” (of which I have only the German translation) both make no mention whatever of 57mm guns being mounted, even experimentally, in T-34s.
A useful post from Scott Fraser on Armchair General https://forums.armchairgeneral.com/forum/historical-events-eras/world-war-ii/armor-in-world-war-ii/soviet-armor/154615-t-34-57-tank-destroyer gives what seems to be a pretty definitive account of the 1941 programme, and gives the fate of each of the ten tanks in the programme, together with their chassis numbers.
According to tank archives http://www.tankarchives.ca/2013/07/soviet-57-mm-guns.html there were four vehicles in the 1943 programme, based on the 1942 model of the T-34. They do not seem to have seen action.
It seems quite a jump from 14 vehicles to 324, so I wonder where Mr. Tucker-Jones got his information. It would, however, make sense of bothering to lay down boekomplekt norms for the vehicle. One might perhaps explain the 1943 directive as being the result of a keen staff officer thinking ahead to a programme that did not in fact materialise, but it is harder to see why anyone would have bothered in 1944.
You will see from the piece I posted on preparing for tank shooting at Kursk that there was also a claim of 57mm guns being fitted in KV-1s, and the author gives no source for the claim. In support I have been able to find only an entry by Henk of Holland https://henk.fox3000.com/t34-2.htm which also contains the useful note that Factory 92 manufactured 172 ZIS-4M guns in 1943 before switching over to the 85 mm, and in 1944 turned out a further 19 ZIS-4Ms. That seems to put an upper bound on 57mm gun tanks about half that claimed by Anthony Tucker-Jones — I’d be interested to know his sources. Of course some of the guns fitted might have been ZiS-2s, as I believe was the case for the 1941 batch, or ZiS-4s.
Unfortunately the web now seems to be awash with witterings from “World of Tanks” and “War Thunder” whenever one attempts to google on questions like this, and things are not helped by the lamentable failure of many writers to quote their sources.
I’ve seen photos of both 1941 and 1943 models of 57mm-equipped T-34s, but have never yet seen a piccy of a KV-1 so armed.
All the best,