In chinook we used:
SRCREV_chinook = "ad245bdd60434dd46d6461f585d49db1b3b0d75b"

for dab the plan is to set the 'tag' once in the poky-agl.conf for the distro

e.g.

AGL_SRCREV_TAG = "4.0.0"
or
AGL_SRCREV_TAG = "dab_4.0.0"

and in the recipes use:

SRCREV_dab = "${AGL_SRCREV_TAG}"

This will simplify the uprev'ing.