When is a MVS cart ORIGINAL

Hi,
Some months ago i started to collect MVS games.
Recently i found a bootleg of Metal Slug 1 in my collection.
The reason was that occasionally it didn't start.
When i opened it, i found the most terrible versions of glue Roms i have ever seen in my life and as a computer tech i have seen a lot.
The chips were mounted on small PCB´s with soldering legs and some kind of glue was poured on it to protect it.
After this dicovery i started to reinvestigate my hole collection and found another similar case.

After that i was somewhat concerned about the authenticity of my other games.

I discovered that most of my games had a serialno. but others didn't.
I started to open the games that had none, but found what appeared to be original Mask-Roms not Proms or Eproms.
I know that there are conversion from AES cards but this would only make sense if the MVS price is higher then the AES counterpart.
So what is the reason that i have so many labels that seem to be printed with a laser printer and do not have a serial no.?

I would be nice if you can help a newbie to find criteria which can be used to identify
origianl carts.

cu
Scalar

[ October 24, 2001: Message edited by: Scalar ]

Usually, when in doubt look for SNK on the boards. That's at least a start.

Most bootlegs don't have the official SNK boards.

As far as conversions go, they only convert certain games and I really haven't heard a whole lot of AES to MVS because on average the MVS price is less, like you mentiong, but there are a few occasions where the reverse is true.