No, I used to prepare these Maxima.app-s.
The way you do it:
Compile maxima with sbcl with configure & make. Then 'make install'
with DESTDIR or something like this into a folder on your drive.. Then
you open up previous Maxima.app and switch the old maxima with the new
one (share dir and other things). Then perhaps correct the version in
plist... also Maxima.app uses a modified 'maxima' script in /bin/
which you shouldn't overwrite...
If you understand compiling, you should know how to do it.
Also if you plan to distribute it you should use 32 bit version of
sbcl -- for that you have to change some flag in the sbcl compilation
process ..
It's easy but there are some gotchas.
Regards
Ziga Lenarcic