Rick, what great luck you have had in being able to find an original trigger guard for this. Personally seeing as you have the original pieces for a pattern I think that many would have opted to have the new one engraved to match the rest of the guns original decoration. I know that there are restorers out there that could match the patina up again after the engraving had been done. Leaving it as is though has its own merits too, the main one being saving money. If this was mine I do believe that I would have made the same decision that you have, but only for the reason to save funds for my next potential purchase.
Best,
Robert