Hey Cesar, where did you download that Mossberg 500 manual from? I have a 500 I picked up for $200 many years ago, and I don't have a manual for it.
I got it from their website some years ago but I'm not sure that particular one is still available. Mossberg still has a section with manuals but they seem to change and update the manuals from time to time. I actually don't like the Mossberg 500/590 manual they have up there now as it has registration lines to cut the pages from an 8.5x11 sheet which means it doesn't work when you ask Acrobat to print it out as a booklet. It would work if you want to print it out, cut it and spiral bind it I guess. If you want the one I have, PM me with your email address and I can send it to you, it's actually not a very big file.
Anyway, for what it's worth, their website is here.
https://www.mossberg.com/support/owners-manualsI also had a 590 with no manual and after I bought a 500 which came with the manual I wanted a second copy. I'm never planning to sell any of these, but I like having one manual for each firearm as it just doesn't seem complete without it. What really spurred this project (which I'd been mulling over for several years) was that I won a CZ40B in an auction. I'd been looking for one for several years but the one I got didn't come with an original box or manual (or any of the other usual goodies). Fortunately I was able to download the manual for it online and printed it out. I had just gotten my new color laser printer working again and wanted to try the booklet print feature in Acrobat, which turns out to work remarkably well if the document is properly formatted. The trick is you can't have the whole page scanned like I'd done for several publications. You have to have each individual page as a separate sheet in order including any blank pages. Once that's done, the program will sort them out properly and place them in the correct order to print out the whole pages front in back in such a way that you put them together and fold at the middle and they're all in order. It's actually quite remarkable. Anyway, the CZ40B manual came out so good I started printing out others which is when I realized my SKS manuals weren't quite up to snuff. Only my first SKS ever came with a manual and the few manuals I'd downloaded were very low quality. I still need to scan a few other manuals I have (like my MAK-90 and Norinco UZI manuals), but I finally have the ability to print everything out properly.