For a long time bent back hammers were okay for mounted shooting but not for us "ground" shooters (external modification rule). More recently there have been some changes that I don't fully understand but have something to do with whether a manufacturer offers that style or not. Thus, Ruger had come out with a Montado (a Vaquero with a lower hammer spur) which originally was for mounted shooters but is now okay for all SASS. You could go to the SASS Wire and ask, but basically I don't think it would be SASS legal since no manufacturer offers it as a standard item. Some local club shoots might allow it.
p.s. Navy Arms is an importer, like Cimarron, Taylors, EMF etc. They import mostly Ubertis. Back some years ago, it was Val Forget of Navy Arms that got Uberti to start making some percussion pistols and everything grew from that. Something like that, anyway. Val has passed on but the company is still run by his son Val Forget III.