My B-I-L was on Resupply to his Bty (in Fodens' possibly DROPS) His Bty were M109A2's.
Italeri do an A2 boxing, which is ok, with a bit of work & new tracks, pops up on e-bay now & then,
There is a new mfr
KINETIC announcing an A2, but box-shots only so far.
RIICH MODELS announced an A6, but box-shots only so far. Their offerings seem .... similar to Kinetics, but the more the merrier!
I don't know of specific decal sets for your Bty, but you can use one from e.g.,
here (assuming non-commercial (fair-use) for your own consumption, & not for monetary gain or re-sale)
Resize to suit & print on decal paper.