Dad recently passed away and left several rifles and pistols. One of them is a model 1906 Winchester pump .22short, long, long rifle. It has a serial number that shows that is was manufactured it was in very good shape. However, dad against my wishes took the weapon to the local gunsmith and had it re-blued. My question is this, did this destroy all collectors value?

That depends. Did they buff it to death and round over all the edges? If so then yes it probably lost 75% of the collector value.
If they did a first class job, it still will have lost some value, but a lot depends on what's out in the marketplace. Watch Auction arms and gunbroker for a few months. You should get a pretty good idea what to expect should you ever want to sell it.

There is not a more fun 22 to shoot. I would enjoy it and teach my children to shoot with it. Being small it is perfect for most youngsters. I have my Grandfather's o6 which was lost on the farm for a while and when found wasas in very poor shape. It still shoots great though.
Judge Sharpe

It's a funny thing, I had no intention of ever letting it go for any reason, I just wanted to know for insurance purposes what the weapon was worth.
Grandpa used to let me shoot "pot-guts", ground squirels that held around the garbage dump up a canyon near SLC, nearly 50yrs ago now. I probably ran 1000 or so rounds thru it.

I took my hunters saftey class with the little 1906 and won a bet in the process. The fish and game officer bet me that the safety, which is the "1/4" pull back on the hammer, wouldn't or didn't work. He lost! By the way, It still does.
The funny thing is, if you didn't know the truth you'd think the little 22' came of the assembly line last week. The lettering isbright and sharp, I can't find any pitting inside or out and the little thing shot just fine at the pistol range (25yrds.) a few days ago.
I have 2 sons, the only problem is, which on is going to get it. Both of them love to hunt and shoot.
Maybe I'll just let them fight it out.........