Beck Number	Mission	Description of Cachet	Postmark
B515	GT-3	Missing Silver	USS Intrepid (PRS)
B5791	GT-6	Plain rather than Textured Background (similar to B610-B613)	USS Ponchatoula
B5811	GT-6	Plain rather than Textured Background (similar to B610-B613)	USS Cochrane
B5821	GT-6	Plain rather than Textured Background (similar to B610-B613)	USS Rupertus
B5831	GT-6	Plain rather than Textured Background (similar to B610-B613)	USS Renshaw
B7871	Apollo 10	Plain rather than Textured Background	USS Princeton
B7881	Apollo 10	Plain rather than Textured Background	USS Chipola
B874	Apollo 15	Missing Black	USS Kawishiwi
B8741	Apollo 15	Missing Green - since the Beck number was printed in green, the number is missing from this cover	USS Kawishiwi
B8961	Skylab	Missing Green	USS New Orleans

Assumed Beck Number	Mission	Postmark
B515	GT-3	USS Intrepid (PRS)
B561	GT-5	USS Lake Champlain (PRS)
B697	Apollo 202	USS Robert A. Owens
B840	Apollo 13	USS New
B861	Apollo 14	USS New Orleans (PRS)
B863	Apollo 14	USS Spiegel Grove

Beck Number	Mission	Description of Cachet	Postmark
B515	GT-3	Beck printed cachet on back of cover with both a Navy cachet and a Project Gemini cachet on the front	USS Intrepid (PRS)