Serial numbers on some guitars are on a sticker that can peel off.

Some guitars have serial numbers at the base of their fretboards, some have them in a pickup cavity. Not all have them on the back of the headstock. I've not heard of a Samick guitar being faked, but I suppose there's a first time for everything.

What's the issue? Is there a problem with the guitar?
im just worried on my investment.. it was my very first electric guitar. in the same way i got surprized about this spanish ads that's carbon copy of my guitar..

i cant take photos of my guitar because its still with the guitar shop.. i brought i there to have proper set-up and intonation.
Lots of guitars look alike, there's gotta be thousands of different copies of the Stratocaster. And Samick is more known for value than desirability, if you like the guitar and it plays fine, you're set. HNGD!
Fender Mustang/Derfenstein DST> Boss Power Wah> Pedal Monsters Klone> Bogner Uberschall> Walrus Audio Janus> Randall RM20> Line 6 M9> Randall RM20
Guitars are never "an investment."

That said, Samick is perhaps the largest instrument manufacturer on the planet, with plants that make guitars for a wide number of brand names and interest in other plants that make pianos, orchestra instruments and more.

It's not unusual to find the same design showing up with a lot of different brand names. This was common when Japan was the predominate "offshore" manufacturer back in the '70's and is proving true with plants in Indonesia, China and Korea these days. It IS a bit unusual to find the name Samick on a guitar (I have one, too), since even Samick's own lines of guitars have brand names like Greg Bennet, etc.