Instauser, gid, Leopard vs. Tiger and Panther vs. Jaguar

The Instauser script includes the following:

/usr/bin/dscl . -create Users/instadmg gid 501
...
/usr/bin/dscl . -create Groups/instadmg
/usr/bin/dscl . -create Groups/instadmg gid 501

It appears that Leopard abandoned the philosophy of every user having a unique uid and gid, and instead now even administrators are gid 20 (staff). Tiger and Panther created a new gid for every new uid (for every new user), while Jaguar and before used gid 20 for all users.

Should the “501” in the first quoted line above be replaced by “20” and the second and third quoted lines be removed? Either way is legal I believe, but are there other ramifications besides the possible issue of all local users having the same gid?

– Patrick