ORIGINAL: pattoncommander
About half the M-46s in my Battalion were converted veteran M-26s with some being reconverted M-26A1s. The Marine 1 & 2d Divs had the newer stuff, having been able to get fully equipt before deployment. Our company had 5 or 6 tanks damaged 46s returned as M-46A1s, but the Army had to piecemeal everything and there was no ideas about getting new tanks...just upgrading as we went. (The 46A1 had only internal changes with relocation of the driver's control panel moved from center behind the front plate to the right of the driver.)
Many WW II tanks also served in Korea and beyond. Even obsolete Stuarts served through the entire war and were used as armored police or border security for a short time after 45.
Agreed, but that speaks to WWII reused tanks in Korea which is not totally representative of what some are modeling. So a WWII tank can almost be modeled anyway you want as there probably is good photographic evidence confirming it. From almost new to four years of a hard service life. Throw some dust and a few nicks on the hull or do up something like Ausf has done and both can be considered prototypical of a WWII tank.
As Ausf has stated be mindful of the trip to the front but some of the tanks also had paint jobs while in the field. Shermans were knocked out easy, but a lot of times they were repaired, "cleaned up" inside and back to the front with some new paint, so literally just about anything goes.