TM Glock 26 - Guarder serial tag fitment?

[Opossum]

So I bought a TM Glock 26 and Guarder steel slide kit for it. The slide kit came with a cool replacement serial tag but I can't for the life of me figure out how it fits. It seems to kinda fit one way, but nothing holds it down and the tabs interfere with the slide.

I know airsoft stuff is designed not to fit, but that was the last part I expected to have trouble with! I thought for once I'd put it down and ask for help rather than start modding it to fit.

Cheers!