I don't think HK ever customized the PSG-1...so with the iron sights, I'd say that's no PSG-1.
I've never seen a PSG-1 with that HK bi-pod..but, I guess it would be quite possible to attach it.
But still, iron sights on a PSG-1...? Nah.... :?
ed: By the way, it doesn't seem to have the standard MSG90 barrel profile...but that doesn't have to mean a thing....