I found a Saturn 1b model here:

 

http://www.the3dstudio.com/product_details.aspx?id_product=64604

 

Not cheap, but there is an obj version that you can import into Poser. I've never bought from the site, but it's all I could find. Might also try turbosquid.com. I got some hits there but the command module looks wrong.

 

If ranman38 takes the time to build one, it will be worth the money.

 

good luck