Not my auction, just thought someone here might like it.

http://cgi.ebay.com/Vintage-Rare-1903-Sp...=item35b0ddcafa

Looks to be a Parker Hale PH16D receiver sight, commonly fitted to Mossberg 42M .22LR target rifles for the British market. The trade name for the PH16 was the "Sportarget" to denote that it was a "dual-purpose" sight for both sporting and target rifles. It came with different bases to fit a variety of rifles, with a letter suffix used to identify the application. The seller's description on the eBay auction is incorrect, since the Springfield 1903 would use the same base as the Mauser 98 which was the PH16C model (note the base on the one shown would be on the wrong side of the receiver).

Nevertheless it's a well-made sight that someone might be able to make use of or adapt to a different rifle. FYI, here's a list of the applications for the PH16 and a link to some information on Parker Hale sights in general http://www.rifleman.org.uk/BSA_sights_and_accessories.htm

PH16 BSA Sportsman and similar
PH16B ditto, with 1/10" higher line of sight
PH16C Mauser 1898
PH16D Mossberg 42MB
PH16E Mauser .22LR with grooved receiver
PH16F SMLE
PH16J Rifles w/flat-side receivers 1.25" wide
PH16K ditto, 1" wide
PH16M Webley & Scott Mk.3 air rifle
PH16N Brno rifles with grooved receiver, .22RF & .22 Hornet

Have had one of the 16E sights on a .22 Mauserfor upwards of half a century now and it is an excellent sight. The sight staff folds to the side so you can use the open sights on the barrel. This Sporterget line of sights was not the big heavy target sights that PH made for heavy target rifles but they were precise enough for anything but top line competitiion.