Gutted an existing bathroom. Tub installed in alcove.

The tub/shower alcove will evenually be fitted with a glass shower door, bottom track on the tub of course.

My question:

Should the framing of each end wall include a stud precisely where the shower door wall jambs will be fastened, allowing for screwing the jambs through the tile & Durock directly into the stud

or

are some type of wall anchors sufficient?

I meant to put a 2" x 4" behind the far, non-plumbing wall but forgot! Only 2 pieces of Durock and some plastic there now, not that difficult to remove and fix if necessary.

TIA!