Prior to posting, I took it all the way apart and replaced all the o-rings, seals, and regulator seat. I put in a new main spring and replaced the nubbins in the barrel and put in new barrel o-rings. I oiled it up and gassed it up. I put a half hopper of paintballs through it to test fire and do an initial chronograph. Shooting fine and ready to go.
Older Minimag with serial number MM084XX series. Original hose with a internal filter. It does have the aligned air passage hole in the regulator. The main body does have the larger opening and recess in it. If you have an Automag rail with a pump slot and a pump kit, you could convert this to a pump-action marker.Great classic mechanical paintball marker. I don't play anymore and don't anticipate playing again going forward, so clearing out gear boxes.
Please be aware that due to lighting, camera sensors, and your device screen settings that the color may vary slightly in person from what you see on your device.