You dug an old Colt pistol with a four digit serial number and was wondering if there is a way to track it to its original owner?

Of course there is a way. How much money and time do you have to spend?

Start with contacting Colt for a "factory letter". Give all markings on frame and barrel(look under the grips,also). Pictures are helpful.

Now, write down what you already know about the gun. Was it grandpa's gun that he brought home from WWII? Did you buy it from a pawn shop last week?

Go from there.