I notice alot of pics of SAR1s with some really nice exterior sheen. My question is, do you wipe down the exterior with anything to keep it looking nice and smooth? Mine has that flat finish and scratches and small blemishes here and there, but I figured if I used something like a dab of oil on a rag and wiped down the whole exterior this wouldn't hurt, or would it? I just want a nice satin/ semi gloss sheen to the exterior like Ive seen on some SAR1 pics on this forum.

I suspect the shiny ones were refinished or had a distinct light angle. You can wipe them down with a VERY thin film wihtout making them slimy to hold. I actually do that with one I have blasted and parked.

Boiled lin seed oil

CLP.  wood loves it too.  Just a lint free cloth and just a few times over.  =)  

Cleans.  Lubricates.  Protects.   Well, the outside of the guns, anyway, I'm moving on to Militec-1 or a Synthetic [Motor] Oil

Break-Free is a fully synthetic product.