I found NAC's very rarely where they came with the MS8 29 monitors. Supposedly really early NAC's had MS8s at least from what I read up on and seen.
Parts did get swapped around some though too thats something to keep in mind when discussing the monitors on Astros some of these cabs have a long history.
Personally I have seen where the remotes on early Astro 1's not the NAC. Gets mounted directly to the CRT frame (where the control cut outs are) under the bezel and the cabinet has no provisioned holes drilled for mounting the remote board at all from the factory, which is kind of wild to think about.
However all of your control connectors should be in the control panel area. If its not its possible that for some reason the mounting plate for the connectors was lost or not screwed in.
The the kosher way it was done from the factory by Sega was to have the control harness's plug into a connectors under the CP.
Congrats on the NAC though those are tanks and great cabs to start on!