Mp5 RIS Rail & P90 Sights Help!

[Slodin]

I raise two questions today.

First is Mp5 RIS Rail:
My friend bought this CYMA CM041 used, but it didn't come with the RIS rails. Although I can see there are certainly screw holes for the rails on the handguard. sides and bottom.

Anyone know where to get those rails? I searched and all of them are the whole assembly in which we only need the 3 rails....

Second P90 Sights: (this is more of a side question since I'm posting anyway)
My P90 doesn't have any sights. The rails on top does have a little notch, but isn't helpful at all when I'm masked. I wonder what do you guys like for a sight on a P90? I'm just looking for a sorta open sight red dot, wondering which is better..

Eotech? Reflex redot? Just got 50 bucks from a really easy job, so looking to buy myself a xmas gift..Yeah xmas is over but I didn't get myself anything yet LOL

Thanks for any input