My question is-is the white form you're talking about a 4473 (ATF 4473)? If so, the ATF sent us FFLs new designed Yellow colored forms stating we could NOT use the White forms any longer and doing so would be a violation. These "new" forms were sent to us earlier this year!
I would ask Cabelas why they're using the "old" form that is white when they're supposed to use the "new" yellow form! I would NOT fill out the white one due to possible need to fill out the yellow one later once they received them from the printing office! Then they have 2 forms in their files and would need to destroy the white form which is a violation on their part!
Then again, you were doing what the FFL (Cabelas) said to do and their supposed to keep up on the laws! If their having you do the old white form because they haven't received their New supply of yellow forms yet then I'd purchase the rifle, fill out the form and let them worry about the rest!!! Can't come back on you as they are the transferor!