Is this bag fake?

You might have more luck in the new "Authenticate This" forum.

That being said, are Moni Monis faked yet (I hope not)? The outside looks OK, but the nameplate on my MM is engraved brass on top of a leather patch, not just leather like this one. $300 is a pretty high price for a used bag with no dustbag, with shipping it comes out to $315. You can get one brand new and guaranteed authentic at Adasa.com for $396 using "grechen20" for 20% off, and they have free shipping.
 
I believe its an authentic Splendor, but also that its been carried way more than a few times.

I agree that you can probably get a better price on a new one somewhere else.
 
My Splendor has the brass tag on top of the leather one inside. And my shoulder straps and handles have little metal studs (check out the others on ebay to see what I mean).

Also, this bag looks shiny, nicer than mine, which is very distressed looking, no shine whatsoever. Maybe this bag was treated with something to make it shiny. And I would not ask someone to pay $300 for my used bag, which has no damage.