ST bass neck on concordII 84 body

Heyup
There's a 21 fret ST bass neck on ebay, been defretted and I'm wondering what I'd need to do to fit it on my 84 CII bass body,  the CII has 22 frets.  Both are 34" scale and roughly 62mm heel. 
I'm aware (I think) even though there's no frets I'd still be using the fret markers,  is this doable without cutting into the body?

i imagine you would have to leave some space at the bottom of the neck pocket, to compensate for the 22nd fret not present on the ST neck

so my guess; no cutting needed

Thanks Mike,  that'swhat iI was thinking, maybe make a small chock from maple 🍁 to plug the gap when the fretless neck is on. 

Cheers!