Only if he tests for it, which he likely won’t if you don’t give him a reason to. I’m not certain, but it may go against his ethics board (or even the law) to run a test like that on an adult without that adult’s permission.
Here’s the problem with telling him honestly: some physicians are going to latch on to the fact that you’ve abused substances for the purpose of bodybuilding in the past, and not treat your low testosterone because they may be concerned that you’re really just looking to ‘juice’.
Still, telling him may be the best route. I am not familiar with your body chemistry, and it’s possible that he will be able to find something relevant to your case that could affect treatment.
If you want to go the honest route: be very honest and forthcoming with him. Tell him that you were on propecia for 6 months, and that you have only ever taken a single shot of AAS.
Try to avoid telling him what you think the problem is, as that will color his judgment; show him the lab results, mention that you are concerned about out-of-range levels, and if he’s a competent physician he’ll decide that you have primary hypogonadism and hopefully prescribe TRT. If he doesn’t immediately, you may have to advocate for yourself; mention that, at your age, testosterone levels should be in the 600s at the least, and that testosterone in the 300s is very low, and that it’s negatively affecting your life.
It would be useful to get more lab tests, but you need to wait for the AAS to leave your system, which could take a few weeks. The following labs will be useful:
Free Testosterone
SHBG
Total Testosterone
TSH (TSH can vary, you’re concerned about possible hyper, so get it tested again just in case)
E2
Cortisol
Vitamin D25-OH
Do these tests as near to 8 AM as possible (7-9 AM should be okay).
Yes. You should be getting proper treatment for primary hypogonadism through a physician in some form. Avoid illegal, unmonitored juicing. Treatment for primary hypogonadism is TRT. See stickies for more info.
Atrophy isn’t always an issue of size, firmness, etc. You can have functional atrophy without noticeable symptoms.