I don't know if this will help or not, but it might.
RMC/Ox-Yoke carries some replacement parts for T/C locks and most of the internal replacement parts for Lyman (Investarms) locks. They state the T/C parts are for the T/C flintlock, but I think the internal parts for the flintlocks were the same as for percussion. I know the T/C Patriot/Seneca lock
plates were smaller than the Hawken/Renegade lockplates, but I don't know about the internals. It would make since for T/C to have used the same internal parts on all of their locks to simplify inventory.
The Lyman/Investarms locks have a mechanism and coil springs which appear very similar to the T/C locks. I have not done a side-by-side comparison, though, and I don't know if any of the parts will interchange.
Anyway, they have the fly for T/C locks, and the coil mainspring for Lyman/Investarms locks. It might be worthwhile to call them and ask if these parts will fit your Patriot lock.
This outfit,
Classic Firearms & Parts, has a bunch of T/C Patriot parts shown, although the mainspring and fly are out of stock. Numrich Gun Parts Corporation carries some T/C parts but I don't think they have the ones you need.
In my opinion, you best bet may be to call RMC/Ox-Yoke and ask if their replacement parts (as above) will fit a T/C Patriot. If not, your best recourse may be eBay.
Best of luck to you!
Notchy Bob