To be honest the kit just needs some minor tweaks to be an Operation Cobra M4a1 76 mm. Most of what is needed is in the box. A few minutes of work and some new decals and you are done. After all the "discussion" in that thread, it boiled down to a few simple changes any basic modeler could do. So including those tweaks as a "by the way" for that kit would be helpful.
1. Drill out the position of the forward radio mount.
2. Place a piece of Plasticard under the hole.
3. Add a disc of plastic to the correct dimension.
4. Add 4 small bolt heads.
5. Using a very thin plastic card, cut out a fillet for the turret roof between the hatches and glue it in.
6. Smooth the edges of the fillet in with Mr. surfacer or thinned putty.
7. Leave off the ventilator cover on the rear of the turret.
8. Use the non-threaded barrel.
9. Lower the spare barrel supports and MG storage mounts.
10. Get proper markings.
This link is a great visual aid.
http://the.shadock.free.fr/sherman_minutia/index.htmlTo be honest the hardest part is finding the proper decals.