probably, Porsche are known for adding lots of usually optional equipment for free, esp. options that other marques charge for - they are extremely generous like that....
I think a few exist as special orders for very tall people, but if you really want one without then I guess it would be possible to remove the sunroof and weld shut & repaint.
My 1990 964 hasn't got a sunroof, no mention on the options list of a sunroof delete. I thought (i may be talking out of my a*se) sunroof's were an option back then.
Recall when I bought mine that a sunroof was a "mandatory" option. I think this was just a trick to get the list price down & then instantly stick £1400 on it before being allowed to buy the thing...