Nice work there is a lot of prep work goes into 3D prints just to get them looking as good as they can.
Recent addition to the CRL's
L2 and above
3-D printed blasters can not contain visible print lines, and must be sanded smooth for a more realistic appearance.
You may want to check in with your GML (garrison membership liaison) some are a little more picky on printed weapons than others and may request no lines be present for base approval (although you don't need a weapon to gain base clearance )
Ok so to be a little picky, looks like your scope will need some prep to remove the lines, this may have been a late addition and you've not tackled it as yet. Can also see a few other areas, right side front folding stock (actually both sides front). Inner silver bolt as well.
Scope rail is bent, an aluminium rail would be better for strength. Also note the height at the front and rear of the scope rail are different.
Can see some lines in the T tracks as well. There are a few others very faint, magazine end cap and henglster.
Also appears some lines on your handle, just visible
I like to sand (ok I don't like to sand) every piece before adding any spray putty (other parts of the world call it primer/filler) we have that too but it's just not as thick as spray putty. I put on 3 to 4 coats depending on how deep lines/scratches are. I know many use the blade putty but it's a lot harder to sand in comparison with spray putty. I sand wet with 240 grit wet/dry sandpaper and also add some dish washing liquid to the water, helps to stop clogging and makes the sandpaper last a little longer. Blade putty is for anything else left behind, and a good way to check this is give it a guide coat of black, a very light mist coat, once you start sanding you can see if any black remains that's were you need to fill. Coat of primer and a hand sand with 600 grit and it's pretty much ready for paint.