I had suspected that there was a sight protector on in the first photo.

Whig is correct about the serial number.  You are among friends here!  If it is listed in the SRS data, the full number is required to determine where it was issued after manufacture. 

A word of advice regarding the sling:  If you intend to shoot it and use the sling for support, as in shooting from position, you might consider removing the sling and installing a newly manufactured 1907 sling from Turner or one of the other reproduction sling companies.  As Butlersrangers said, that original sling can be valuable.  No sense risking damage!

As for shooting it, if you plan on shooting cast bullets, then by all means, slug the bore.  However, if you intend on shooting factory ammo or reload with jacketed bullets, then go ahead and bang away!  Standard .308 bullets will be fine even if your bore is slightly oversize (a normal occurrence with Krags).