[DeTomaso] Spare tire question

[Christopher Kimball]

I have a pre-L '72 that, when I bought it from the previous owner, came with a collapsable spare tire.  Although I'm pretty sure the neat little vinyl cover with the DeTomaso logo on it isn't stock, how do I tell if the spare tire itself is the genuine article?  It's far too big, even in it's pre-enlarged state to fit in the small, circular shape in the back trunk (in fact, I don't think any spare tire would fit there, unless it was for a Tonka truck).  Or, is that space in the trunk really for a tiny spare?

Thanks,

Chris (who has owned his Pantera long enough that he should know this stuff by now...)