I just received a Wahl all metal pen from an eBay auction and spent a while cleaning it up and installing a new sac. I got it for a fairly reasonable price, but it was hard to tell from the original pictures exactly what I was getting. It appeared to be a badly tarnished silver pen, but the seller said it had "Gold Filled on Sil" around the top of the cap. Here is the pen, as it appeared on eBay.
I was pleasantly surprised as I hand polished the pen using a bit of Simichrome, when this pen started to emerge:
I found the pen in the 1928 W-E catalog. It was listed as one of the new Wahl Precious Metal pens. It is gold filled on silver, with a pattern then cut down to the silver on portions of the pen - thus creating the two-toned gold/silver look. This design was called Wedgewood. Here is a close-up of the pattern:
Not much problem restoring it. The hardest part was attaching the pressure bar to the lever - it came out while cleaning out the old sac. The pen is almost perfect - there is a tiny ding on the cap rim. But all the gold fill is intact - no brassing at all. This is truly an elegant pen.