I have both, and consider both to be production pistols, although the Professional is produced by the Springfield's Custom Shop. In my opinion, anything they make 5000 of, cannot be considered a "custom gun", but I guess that's semantics.
I believe you're correct on the hand fitting––the Pro having more. I believe also, that the Pro has most if not all of the internal parts (hammer, sear, disconnector, etc) made from forged bar stock, rather than the dreaded MIM––a pseudo casting technique. I'm not mimophobic, so that's not an issue for me. The Pro has genuine Novak sights, while the TRP has a clone. The Pro has "Black T" finish, while the TRP has the SA house Armory Kote. The fit and finish of both are comparable, but the Pro does win by a nose.
The TRP has Springfield's Integral Locking System (ILS) while the Pro does not. The Pro has a full-sized (0.090" dia) titanium firing pin while the TRP has the wuzzy small diameter (0.070" approx) titanium pin. Both pistols can be sold in California.
The Pro was tested to the FBI's procurement specification which required it to be subjected to all kinds of harsh environment and still perform. To my knowledge, the TRP has not. The Pro has a higher (smaller group size) accuracy requirement than the TRP, but the difference isn't that much.
They're both fine pistols. Both were good purchases, and I would do it again.