No, do not make an offer until all of your questions have been answered and you feel comfortable entering into a deal. Once you do make an offer, see it through. If there is a subsequent problem with the item (it is damaged in shipping, or misrepresented in some way), that is another matter. But backing out of a deal because you want to "secure a place in line" before you have done your homework is absolutely not the right thing to do.
By the way, and for what it's worth, I value a seller's feedback far more than I value photographs. Most folks here--especially experienced members--are meticulously honest. If there is a flaw in an expensive piece of gear, of course I would want to see it. But I do not need to see photographs in most cases on anything but the most expensive gear, such as amps or speakers, and perhaps not then, depending on the seller and the description.
I almost never buy from anyone without a solid record of positive feedback.