if it still got box, should have Sony Malaysia Sticker.
plus, I think the My set should have its own model number.

Should be

PCH-1006
Last two digits refers to Hong Kong set & Singapore set or kinda for Asian set.

http://www.edepot.com/playstation.html

Cross ref with box and console number
https://support.us.playstation.com/app/answ...-serial-numbers

If you are talking about GAME CARDS... VITA is "region free", simply put you can play games of any region on VITA of any region.
BUT, when it comes to DLC and Digital Games... that's different story, "Regional Restriction" applies to these sucker terms!
Meaning, you can't download extra content from JP PSN for a US ver (R1) game, and so on...
Digital Games are stuck with the PSN account you registered with, in a sense, it's "region locked" for Digital copies! ... for now? (Don't know what'd happen after the release of PS4 after all the claims they made with DIGITAL FREEDOM, sorta...)
FYI, PSN accounts are US (R1), Japan/Europe (R2) and Asia (R3), you can simply google for more info.

Some people have issues with credit card while some don't... Something to do with credit card verification? I don't know... I used to have problems with Asia (HK) account but after few tries, I could pay with my Hong Leong CC... To answer your first question, credit card payment is a lesser problem, providing your CC is a legit one, and not stolen card... The DLC, game content availability and Online play are the major concerns (probably trophies not transferable after switching to another account... too?)...

Last one... Apologize, I hardly follow up on the VITA pricing nowadays... Hope someone could get you the latest price about VITA!

For physical copies, the carts, yes, you can play in any VITA regardless of which region the carts from, just need to do extra work if you get it second hand...

The game cart!