M1a1 loaded Spartan Bipod mounting with walnut stock

I am getting ready to mount a Spartan Universal Bipod on my M1a1 loaded. I have already gone the route with the Springfield M2 bipod that clamps on the gas cylinder. After seeing the Spartan system ease of operation, I decided I could use with different rifles and did not have to disassemble (unclamp).
Upon inspection with kit the Classic Rifle Adapter (supplied) I noted I would have to drill out the rivets for the forward sling mount. Even then the adapter is longer that the flat area where the sling ring mounted (not clean enough fit for me). Spartan sells another mount (brass for wood stocks) you use a Forstner bit to make the hole and glue into the stock.
For my question of this forum: There is a hole forward of the sling swivel and ferrule, front (about a 3/8" hole). What is purpose of this hole? I am unable to identify on any diagram I have found for this rifle.
Looks like a nice place for an easily detachable bipod to me.
Thank you in advance,
Mike Williamson
From the land of fruits and nuts (CA)