As I wrote in an earlier post, this was a negotiation tactic to appease our European “allies” and induce them to support our R&D on SDI. Reagan had no intention of giving useful technical data to the Soviets. In fact, to the contrary, there was an active and very successful disinformation program during the Reagan administration that leaked faulty engineering specs to the Soviets for everything from gas turbines to oil-drilling equipment. This is all well-documented in many books, one of my favorites being Peter Schweizer’s “Victory”.
SDI was a bluff, there were no actual specs to pass. If there were, Reds could have it as fast as it were first tested.