No such animal as a 2006 SEEG. There is a 2006 SEUC. Depends what he had done. The 103 motors the better side of the numbers say 120 / 115 would cost most people somewhere in the neighborhood of 2500 plus in just motor work that being Heads, Matching Cam, Throttle body whether it was upgraded or whether it was the stock modified. That doesnt necessarily include labor its just a guesstimate figuring 1000 for heads 750 for Cams, 150 Adjustable Push Rods, 400 Roller Rockers. Add avg 700 for pipes if they didnt have them and 300 to 500 for a dyno tune.
Labor on a complete top end on a 103 motor would be about 11 hours at 70 bucks an hour avg for this questimate would make 840 bucks in labor. Labor on a Cam only would be about 4 hours or 280.
If he took his 103 and just added say a 575 cam from Zippers or a 257 from Harley. Zippers was available in gear drive and chain drive for 2006 and the cost would be 330 for the cam and the gear drives are about 350. If he went chain drive then he didnt spend but 330 bucks.
If he went with just a harley 257 cam would produce on the safe side 110 / 110 and it only cost him 4 hours of labor the cam / adjustable pushrods. Obviously he can do more just giving you some rough ideas its not going to much different from what your doing or paying for only difference is his motor is stroked to start and your after Reliability / Good Running.
Another help for you might be to switch out your gearing and give up a 150 rpm and go 337 gearing over the 315 you have you have 25 / 36 counter sprocket and clutch basket. Harley sells the 24 / 37 about 380 dollars.
Hope that gives you some ideas TommyO