Normally, the clutch throw-out (clutch release) bearing is sealed.

If the bearing-balls are worn, it can rattle.

If the the throw-out bearing "arm" is loose (worn ball, for example), it could rattle.

If the throw-out bearing arm spring is loose/missing, you will hear rattling.

http://chevy.oldcarmanualproject.com/parts/1929_54/113.HTM
http://chevy.oldcarmanualproject.com/shop/1948_51truck/51ctsm0689.htm

Tim
1954Advance-Design.com
1954 3106 Carryall Suburban
1954 3104 5-window pickup w/Hydra-Matic
The 216 and early 235 engines are not "splash oilers" -- this is a splash oiler.