Even if the impact on a near-term undertaking is limited, the understanding of comparative capabilities are huge for program management decisions for future iterations.
For example had they realized that the LM the Soviets were building was incapable of working, that could impact the program in huge ways including changing how funding for the US program was structured, rule out or confirm a configuration as viable, speed up development in other critical areas etc...
I think that they would have figured that the Soviets changed something between the production and displayed item. You can't categorically say that it couldn't work. AFAICT, Intel work is rarely that certain.
For example had they realized that the LM the Soviets were building was incapable of working, that could impact the program in huge ways including changing how funding for the US program was structured, rule out or confirm a configuration as viable, speed up development in other critical areas etc...