The SGL-10 is just a Saiga with a different front end treatment at Arsenal USA. The buttstock is still the same hunting rifle type. Did yours have the pistol grip and stock conversion? If so then it would have been done where you got it. If its got the pistol grip and regular buttstock then your guy probably bought a SGL-10 which is actually a Saiga with a AK front end put together at Arseneal. Thats the hard part. Then he added a pistol grip and trigger guard with a normal FCG . Theres different ways to do that. You can weld up the old trigger group holes and refinish the gun or you can use those little rubber plugs which look cheap but are functional.
Nothing wrong with the Arsenal stuff. The way you got it is sort of roundabout but $1000 for a AK-103 isn't outrageous. Theres better ways to do it but parts are strating to dry up and all.