The new ones have a different bridge and the TCI version 58/15LT pickups. You’d likely need to email support for details on the neck angle/thickness.
From the web site:
“Named after Ted McCarty, a pioneer of the electric guitar and musical instrument industry, the McCarty model embodies the most up-to-date findings from PRS and looks back to the golden age of the guitar. This vintage-appointed guitar features a bound, 22-fret Pattern neck, a slightly thicker back for enhanced tone and sustain, and 58/15 LT treble and bass pickups, which have now been through the TCI (tuned capacitance and inductance) process. 58/15 LT’s are a vintage style pickup with exceptional clarity and focused midrange. Paired with a push/pull tone control and a 3-way toggle pickup switch, these pickups provide a complete palette of tones. The McCarty model is anchored by a PRS stoptail bridge with brass studs for added resonance and vintage-style tuners.
“One of my sayings is that everything that touches the string is God – well, that’s really the bridge, the nut, and the tuners. So when we went after the McCarty model, that’s where we looked. These updates make a huge difference in the tone. The guitar sustains longer and the tone has more character,” said Paul Reed Smith. “The puzzle pieces all fit together, and there is no compromise to the integrity of the instrument. We’re very happy.”
For 2020, PRS has updated this model with TCI-tuned pickups and nitro over cellulose (CAB) finish.
In the late 1980’s, Paul Reed Smith called on Ted McCarty to consult with him on guitar design and production techniques. He not only served as a mentor but became a great friend of Paul and everyone he met at PRS. In 1994, PRS released the first McCarty, an instrument that incorporated the full spectrum of techniques and knowledge Paul had gained from Ted as well as his own experiences as a guitar builder.“
All that being said, I’ve begun to take a different approach with my guitars. If I’m not digging it enough to be playing it, it’s getting sold and replaced by something that gets out of the case. No more “having just to say I have” guitars. But if I have one that has a soul when I play it, I might get another one or a newer one, but that guitar ain’t going anywhere! Sounds like you have one you love. Accessorize, don’t change.