The left hand wagon appears to be a LMSR or BR built unfitted vehicle, correctly painted grey for an unfitted wagon, but with brake gear which is difficult to identify. The 3mm model is an LNER 6-plank unfitted with 2 shoe Morton brake, in BR condition; as it has a wooden underframe it would never have been modified. Numbering as shown is correct, with white characters on black patches
The other three are a bit more of a problem, as the answers depend on what period you are modelling, owing to modifications after building. The LMSR built a lot of corrugated end opens, some fitted, some not, but all 10' wb. Their fitted vehicles had a different underframe, so these models cannot represent those wagons. BR built more fitted and unfitted wagons to similar diagrams; the unfitted versions had 2 shoe Morton brake gear with a cross shaft and the brake shoes on the side with the reversing clutch. All would have been painted grey by BR, except some built i 1948/9 which initially only had the steelwork painted.
The fitted versions had 4 shoe Morton brake gear with a cross shaft, plus, of course, a vacuum cylinder and pipes. From the mid-1950s to late 1959 [i.e. the period you model

] all modern unfitted vehicles with steel underframes [with very few exceptions] were converted to fitted. This process mostly stopped with wartime built wagons; only a few late pre-war vehicles were so treated. All conversions were given 4 shoe Morton brakes. The problems arise with the buffers; initially they were given short buffers with an extension collar welded on the extend the length from 18" to 20.5", thereafter various types of self-contained or hydraulic buffers were fitted. As shown, all three are nearest in condition to earlier BR built fitted vehicles [but see later]. VB vehicles had white characters on body colour, no black patches [there were a few exceptions, but these are not relevant here].
So far as the Peco comment is concerned, something has gone wrong, as 1/120 was a vacuum fitted 21T steel mineral wagon. Also, only the LMSR and BR used corrugated ends on wooden bodies wagons; the LNER built both 5-plank and 6-plank wooden bodied merchandise wagons, but they all had wooden ends.
The prototype photo looks as though it may be an SR built wagon, because of the short number, but, if so, is most likely a BR conversion to VB; the SR also used a different underframe for most fitted vehicles, while the photograph shows 4 shoe Morton with a tie bar [which virtually all such vehicles, both built new and converted, had].