Classic Winnebagos & Vintage RVs

i am trying to order new shocks ( NAPA Monroes) and wanted to confirm my chassis and compatibility. I have been told my 73 D-20 with 440 is a RM350, is this a modified 400 chassis?  My chassis plate is unreadable and my DMV VIN starts with a "33". After reading the Chassis VIN thread I am lost as my VIN should start with a letter, like D33.....?


Looks like NAPA has discontinued making theses shocks and selling off inventory. The sales guys said these are for a 300 chassis but I was told I have a RM350 but can't verify. Are there differences between a 300 and 400 shock mounts or lengths?
Hoping to order these asap.

Thanks

M300 (aka: RM300) and M400 (aka: RM350) both use the same shocks front and rear.
Re: Gas Shock Recommendations (http://www.classicwinnebagos.com/forum/index.php/topic,1185.msg30376.html#msg30376)

Great thank you Dave.