Thanks, everyone! Most of the faucets I've seen online have a "P" stamped into the flat spot on the front of the faucet; mine don't have that. I'll cross check the 425s to see if the internals match. I may have my LHBS price out an order 4 of the Intertap springs anyway...if they don't work, I can sell them or just absorb the small cost. Were the 425s plated or stainless?
I know my 425's are SS inside and out. There were some versions that had plastic spouts and guts.