I thought about it a bit more and actually, the weapon specialist kinda covers the sniper and scout area pretty well.
Sure they don't have perception as aptitude, but besides that you just choose the +5 bonus to BS instead of WS. You get the option to choose survival. They start with navigation (surface).
Starting talents are either lasgun barrage or rapid reload and the reload would probably be more proper, though with a triplex pattern lasgun you would be more versatile and could take lasgun barrage for good long range and close range.
the 600 exp you start out with you could buy awareness and stealth for 300 total (200 awareness and 100 stealth), unless you belong to a recon regiment in which case you would already have awareness, meaning it's only 100xp to get stealth.
This leaves you either 300 or 500 xp to buy Deadeye shot if you wanted that particular talent (which is tier 1 and both aptitudes, meaning 200xp).
So, specialists start out with 300 xp and guardsmen with 600. If you wanna be a recon guy or sniper you probably belong in a regiment that would use those people, not likely line infantry (not saying they can't be there, just that it's less likely), so most likely would already have awareness which mean that by buying stealth skill and Deadeye shot would leave you with 300xp, same as a specialist..
If you play that class in a group with the sharpshooters added to the regiment, you start out with deadeye shot as well..
So, basically, no sniper guardsman needed. No scout either. It's the weapon specialist with focus.
Also, guardsmen who become snipers are that way because of training so shouldn't start out as such really, whereas a person from a sniperschool would be a support specialist more likely. Start with 300xp. If you still wanted to make a sniper class.