Here you go guys. I had it done in Oct., 2001.
Had I let Coles keep the single trigger it was, I want to say, around $150 for the conversion.
I checked my invoice and I paid Coles $200 and got back my single trigger. I believe I sold the trigger on Ebay for a little over $100. My trigger was hardly used, maybe had 100 rounds through it at the time. So it cost about $100 out of pocket back then, plus shipping.
Coles did a great job, both trigger pulls were tuned to around a nice crisp 4-5lbs. The also switched out the barrel selector/safety button to just a safety.
I like the gun very much but hardly use it. It's my backup gun, I take it with me in case one of the older SxS's gets a hiccup.
I bought it for myself for my 40th birthday, I got a good deal because the barreles are the wrong way.