There was indeed a PP version of the chassis, usually fitted in the console model (846).
Paul's data shows two variants of the RF section, and two of the power section, but only one IF. All examples I've seen have that blanking plate. I like Jon's comment here:
http://www.thevalvepage.com/radios/rap/846/rap846.htm
I think the most amazing thing about these were that something so opulent was made immediately after the war. Sure, there were a lot of surplus components about, but everything else must have been hard to come by. They also seem to have sold an awful lot of them, judging by the number that still turn up. Or were they all rented, initially?
Nick.