Tastidian asked the Main to get the plans for the standard Energy Golem. I suspect that the plans for the prototype, aka Dorgon, were held in the Deeper Downs, where the development workshop was stationed. Hence, when the Main invaded the Mechanics Base, the Main got hold of the plans for the mass-produced version. I am not sure if Tastidian or the Queen realized that Dorgon is a better version of the Eneregy Golem: they seemed to be pretty busy reverse engineering the original model and searching to destroy the assembly line for the said models.
The plans could've been burned or destroyed accidently when the Main and co invaded the Deeper Downs workshop: I suspect the Main had no clue what the plans could look like, if he saw some technical specs here and there (ie difference between the files seemingly randomly located on the developers desktop and a user manual that comes along with the final product: I suspect many wouldn't be able to recognize what goes with what, or even realize that internal document named "Bob" is a specification for modelling of Dorgon's laser burst!).