Correct stem for a prewar shelby?

[itweighsalot]

Okay, bought a Shelby built Hiawatha with a Shockease fork. Has a stem of the style pictured below, with the core which draws up to expand the walls of the shaft outward. Seems to work loose while riding, and begins to wiggle around. Is this the correct stem for the bike? Should it have the later wedge type? Thanks guys. I rode it today and tightened it down again, seems fine now, but i want the correct parts.

 

[militarymonark]

its prob correct i've had those on my shelbys

 

[J.E]

Thats the same stem I have on my 36 Shelby Airflow and 37 Airflow.