I've never heard this 'Iconic' version of the Altec 604-K but they are built by Bill Hanuschak of Great Plains and based on the 604's I have heard I'd say yeah, they are worth that much.
I believe the woofer parameters on these are very similar to my G's and my experience is that the best cabinet is 9ft3, tuned to 40Hz and using a wide 24" baffle - basically the Altec 620A or a variant. It's not that they sound bad in smaller boxes but you loose bass extension (which is about 40Hz in the big box I'm suggesting) and a narrow baffle kind of hurts the upper bass/lower mid balance which isn't a good thing with these - they can sound forward in the midrange. System matching does wonders for the mid balance but a wide baffle is an important element (IMO).