Could the a/c operate in VNAV & VOR/LOC or HDGSEL for either a LOC ONLY or NDB?
VORLOC & VNAV is SOP for many for LOC Only approaches.
Our SOP is V/S for vertical path if HDG SEL has to be used for an approach (e.g. FMC error, bad coding, etc) however the aircraft will quite happily follow a VNAV path if its coded in the FMC if you use VNAV.