Definately not stock... Are you wanting to replace with the same?
Just about every speaker maker out there has a 3.5" you just need to watch out for the installed height. Anything that protrudes much beyond the speaker's frame is going to interfere with the dash cover bolting back on flush.
It's a good idea to install a set of bass blockers @ ~ 200hz (can get them at any stereo shop) on the dash speakers. This will help keep the new ones from self-destrucing trying to reproduce bass notes they weren't designed to handle.
Doug C.