Usually the 910 has plastic wrap around the clubhead.  A 910 sticker on the club face.  A plastic guard on the bottom plate.  There should also be holographic sticker on the underside of the shaft near the grip.  The grip could be authentic.

Call 1-888-Titleist to confirm the hosel codes. 

RC

You didnt indicate where you bought them, my exp has been titleist serial numbers all irons in a set if they are custom clubs, i think clubs bought off the rack at a retail outlet only have one club, 6 iron i think, with a serial number. titleist doesnt ship custom clubs with plastic on the grips.

The only way you can assure you are buying authentic Titleist clubs is to buy from a authorized Titleist dealer. Hopefully this is where you purchased your clubs, if not you run the risk of purchasing conterfeit clubs.

I have purchased two NEW sets of AP 1 710 from Golfsmith. Both sets had the serial number on the hosel of the 6 iron. Grips were stock Titleist, no plastic.

Good luck,

Mark

Thanks for your comments. I bought these clubs in DC golf show but had them shipped to me later. Also, I just noticed that they were shipped from Acushnet Company.

All custom iron sets have serial numbers on all clubs. The same number...

If bought at for example, Golfsmith, then only the 6 iron.

I was concerned as well as I bought a set that had custom shaft on ebay. 

I got the 910H and they should have a holographic sticker underneath the shaft below the grip

Greg