I just received my 1919A4 from Allied. I have 9 more days to wait for it but when I went to look at it while filling out the papers I had the hardest time pulling back on the top latch cover (it wouldn't budge) so I couldn't get it open. I know it's newely rebuilt but am I doing anything wrong or is it tight just because it's been parkerized? Is there a special button I should be aware of? Any advice on how to make it slide back and forth? Any feedback would be helpful. Should I get a wooden mallet and work it back and forth? Thanks in advance.