Yes, you want the upgrade as not a "global upgrade", why not
as you said before upgrading to 76mm gun (the global version) in the original CoH meant that every sherman you produced would lose its anti-infantry capabilities. my proposition of upgrading the 76mm gun for the sherman (the individual version) individually for each tank means for example that you can have one sherman that excels in good vs tanks duty but average against infantry and the other sherman good vs infantry but average against tanks. here is an example that may explain what i am trying to say. mix and match is always a good idea i say