Here is how I understand your question...
You are an early stage pre-revenue startup in talks with another startup for a potential partnership regarding your product and the final price that you will pay depends on whether your first goal is customer acquisition or revenue.
Irrespective of whether you are exploring partnership or not, valuation in initial stages will be "sticky customer" driven. That is because they are an indicator of product stability and acceptance. Moreover "sticky" customers who have faith in you reduce the probability of pivots and initial cost of development and proving.
In the hockey stick product life cycle model you are really at the bottom of the stick. Therefore stable product with the right value proposition should be your top most goal.
Revenue models will keep changing as you do pivots and market matures so initial revenue is hardly an indicator of your long term sustainability. You can always find a few customers who will pay. But do you have a value proposition that can help you move from the bottom of the hockey stick to the body of the stick where your revenue starts growing on a sustainable basis?
Getting the right value proposition in place and maturing it will be achieved by working with multiple customers, preferably with some degree of differentiated needs.
I would say go for customer acquisition.