1977 MB 450SL Plastic Key

[0330i6]

As the title reads I have found a plastic key in my 77' model MB. What might this be for? Also, can I cut a new key using this one as the match? :dunno::dunno: I'm lost with this one. I have owned the car for about 8 years now, only 60K miles on it and happened to be looking for the real key and found this under the drivers seat...

[Lanc3r]

We're good but I dont know about 1977 MB good. :)

[TXE39]

Valet key? Does it fit the driver's door and ignition but not the glove box or boot?

Wallet key? I don't remember any extra keys with my '77 Mercedes but the ones I had in the '90s came with two remote keys, one standard key (looked like the regular key you have), one valet key (looked like a regular key with a few little differences in the cut and had a round plastic head instead of square one) and a wallet key that was metal and had no plastic head on it.