If anyone with a Freightliner M2 chassis is interested, here is the unlisted part# for front shocks.
It is the 88 Series adjustable shock. #881641SP3 They are about $140 each.
I had Koni's on my 5500 chassis and they really helped control the front over dips and bridges. Although the stock M2 chassis is a 100X improvement over the 5500, I wanted to give them a try.
IAMICHABOD, I don't see bilstein available from them, I searched for over six months to find my source and Bilstein reps and factory techs were no help.
If you are looking for Bilstein shocks here is the part numbers #BIL24-196208 You can only get them from PBS Power Brake and Spring out of the South Bend IN store only. they have them as a OEM piece labeled Firetruck steer axle 60mm. I put these on my M2-106 and can tell you they made a huge ride difference. I would love to hear if someone has compared the two Koni vs Bilstein.