"This kind of Omega"???
As stated, anything is possible on eBay... however what is NOT established is WHICH KIND of Seamaster this particular watch is, but the pics have established that it isn't a "Square-cased" one from the 70's... which you can find as cheap as $50 on the bay....
A note from the watchmaker that serviced it, as to which movement it contains, would go toward establishing a more accurate guess-timate.
If it is a 354 swan-neck regulated bumper, you've got a great deal, anything later, a decent bargain..