need some help with loan questions

280z/300zx

So I got my VPP pricing and found a dealer who is willing to honor it and order my car the way I want. My next step was to got to penfed and get my loan out of the way since Nissan is only given 6.99% on thier loans. My question is this, my car won't be here for probably 2-4 months so how long with my penfed loan be good for? I mean I don't want to go put the deposit down to order my Z unless I know I can get financed. On the other hand I'm not sure how long my penfed check will be good for once I apply for it. Would it be better to order the car and wait to apply for the loan later? Just not sure how I should proceed.

Lastly, the dealer did find a Z almost exactly how I want it. The only thing is that it has splash guards which I do not want nor want to pay for. On top of that they want 500 to ship the car. On the good side I would have the car by the end of the week. Would it be better to order my car and wait or just get this one, not have to wait, but pay 600 more for the shipping and splash guards? Thanks