I'm pretty sure the Compaq Portable III that I sold
in February was an 8088 machine.
Orange plasma display, small lunchbox configuration, etc.  I just went back to the
sales-photos for it and indeed it was badged a III.  It had the standard 640K of RAM
and no expansion slots.  Did they possibly make this machine with different processor
>configurations?  Is it possible yours has a 3rd party processor upgrade?  I definitely
didn't have to run a Setup program to get it going and it had sat idle for a long time
before I powered it up, so I'm fairly certain the one I had didn't have a setup
battery or CMOS setup storage. 
Lunchbox, Plasma, 640k and no-expansion all sound right, however it's definately
a 286, and according to the Compaq literature as well as several web sites I've just
checked, that's what's supposed to be in there...
Here's a guy on Ebay trying to sell one for $500 ... any takers?  :-)
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=4193&item=41…
[I'd even let mine go at that price - found at garage sale for $5]
The setup software was a bootable diskette (like the original IBM-AT)... It definately
has a CMOS RAM and battery, because mine is dead and doesn't hold a charge, causing
the machine to fail it's startup disgnostics if you leave it for more than a day or
two.
Regards,
--
dave04a (at)    Dave Dunfield
dunfield (dot)  Firmware development services & tools: 
www.dunfield.com
com             Vintage computing equipment collector.
                
http://www.parse.com/~ddunfield/museum/index.html