Festus: Sorry, just gettin' familiar. Your Ejercito Argentino Systema is the Colt Model 1927. It is a Colt made 1911 that was manufactured in Argentina on machinery provided by Colt. It was either made under Colt supervison or by the Argentines, directly, but on Colt manchinery. The differences between our 1927s (yours and mine) and the 1911s is the hammer and knurling on the face of the trigger. Otherwise, it is just another 1911 Colt. You are correct in that the finish appears to be a refinish - same with mine.
The only concern about dressing these things to shoot is whether the old steel in the slides and frames will hold up to the use you have in mind. If you intend to install a new barrel, and possibly some sights, and then just shoot hardball or target loads or carry it - no problem. If you want to make a 50,000 round race gun out of it she won't last. You are also correct about the sights - they have the old style narrow front sight which is a bit more difficult to easily see.
If your pistol is sound I can see no reason why you should not go ahead with your plans. The original grips, by the way and as best as I can remember, were a dark, soft wood with deep longitudinal grooves that made it feel fat in your hand. They will accept any grip for the 1911 and all 1911 parts interchange.
Hope this helps. Mikey.