A very, very high level summary:
CK-2998 - first Omega in space. Flown on MA-8 (Mercury Sigma 7)
105.003 - used on Gemini EVAs, including the first US spacewalk (GT-4)
105.012 - used on most Apollo lunar surface EVAs
145.012 - used on Apollo 14 lunar surface EVAs
So the 105.012 and 145.012 are the true "moonwatches", with 105.012s being used for the majority of the moonwalks. Either will make a great find, and generally speaking condition, completeness/originality, and price should trump 105 vs 145, unless you've got your heart set on one particular reference.