Blazer tank differences

[69SCSS]

I have an LMC Blazer tank in my '68, right now it's carburated. I'm swapping on a Sniper and need to swap out the fuel pump. Holley makes a drop in fuel pump assembly that is supposed to work for 73-87 Blazers (HLY-12-308). I'm wondering if it'll work. Seems like the 69-72 tanks are 13" deep, and the 73-87 are 12.75" deep. If the mounting flanges are the same, then it seems to me that it should drop right in. I'd have to compensate for the 1/4" difference only... and with the Holley sock it should work fine.
Anyone have any experience with this? I know there are tons of other options, but this seems to be the easiest swap if it works. Just wondering before I start the swap this winter.

Thanks for any information.