That is a possibility. You can check it by replacing the vacuum line from the FPR with a piece of clear tubing. Failure usually shows on low vacuum - so if you rev the engine, a busted regulator should push fuel into the tubing..... but first you have to have the engine running.

Another test for excess pressure would be to squeeze the fuel line where it enters the the fuel rail and see if the engine will start. If you suspect low pressure, squeeze the return hose from the rail and see if it changes anything.

It'll likely take a bit of poking and head scratching to figure this one out.

Frank