Thank you for the quick replies.
I was finally able to dig up an old scanned copy of the owner manual. It lists the factory tires as front: FLSW 7-16 4PR, and rear: FLSW 11.2/10-24 4PR.
The 5-15 was listed for the L245F model in the manual.
I am assuming that the 4PR means 4-ply rating...