Sumatra 2500 receiver question

OOPS forgot ONE of the 11mm scope rail Phillips screw needs to be removed it acts as an anchor on top of the receiver. Forgot WHICH screw front or rear but for sure ONE of those Philips screws needs to be removed as well. I was gonna do it to check myself but I have a scope on mine so sorry Im not going to take my scope off its shooting too perfect. Yo!
 
My experience is that all airguns have problems. Every gun I've ever owned needed a little love for the exception of my crosman multipump I got as a kid. That thing lasted so long it was rediculous. I wish I kept it. When the cup went bad I just threw it out and bought a new one. Would have had sentimental value to fix and give to my girl. Oh well hindsight is 2020 and all that. 
 
I'd put a magnet on it to see. Use a super long wide flat head screw driver pop off that round rubber plug on the butt pad stick your screwdriver in then unscrew. The whole receiver cover in question comes right off by pulling straight up with a little wiggle fore and aft while the stock stays attached. Yo!

I shoot my Sumatra with open sights

That said, I just put a magnet to the receiver, tilted the rifle, & the magnet slid off.

The magnet did stick to almost everything in the vicinity (receiver screws, receiver cover, breech cover), except the magazine

Hope this helps

Ed