Hi,
Google is happily indexing a site for me, with almost everything a
/cgi-bin/search.cgi?prod_id=4711
style code.
Also, for friendly names, you should probably not just replace html by php, but redirect all names to one single php, with the name appended.
There is a drawback with "friendly names", too: I came across a site that had links like
order_this_product_4711.html
probably also an attempt at improving SE. Now the only part of importance was the product id in the name. So consider a malevolent site puts up a link like
buy_this_crap_4711.html
in some public area and waits for google to find it ....
Musicman