OK ill have a look. I just havent been able to really find any information on SEI oprods is all..she just found 2 SA forged bolts in a coffee can..he was a nice guy..
If you do a search here, there was some good talk about them 4-6yrs ago. I dont see them listed on SEI's site though, so probably no longer available as a part. I suppose you could call them and ask them if they are still available. You could also ask some of the guys here who bought them in the past what they went for back then.
Heres a few threads that came up in a search:
http://m14forum.com/m14/101036-sei-op-rods.html
http://m14forum.com/m14/75332-smith-parts.html
http://m14forum.com/modern-m14/97166-smith-m14-operating-rod.html
There might be someone that would WANT an SEI part..... but the bigger market would be someone who just wants a spare op-rod, so personally thats who I would market it to, and price accordingly. In other words, I like oldflyboy's advice.
Someone is gonna say it eventually.... may as well be me. Ignoring quality completely (seems they do build some fine products) some folks won't touch SEI products on principle alone. You can do a search and judge for yourself whether that is justified.
Good luck and Im sorry to hear for the reason behind the sale. Good parts are priced insanely online these days, so the lady would likely get the most for those parts on gunbroker or such places, if the hassle of selling them like that is worth it.