Factory fuel tank differences?

[Agent915]

Hey all,
I'm ordering a new tank for my C10. It's a '69 cab and frame that I've put a '68 clip on. I found a tank on eBay at a good price, but the companies fitment guide says it will not work, that it will only work on 70-72 models. The reason given was this particular tank was for emissions-equipped trucks. I though all 67-72 tanks were the same, only the sending units were different. Am I wrong? The tank they have for 67-69's is about $40 higher. I don't want to spend $40 that I could put on other parts!

Danny