I would say this is from the 1860-61 era. This general style of Regimental frock coat was quite common amongst the pre-war militia. It is a very well made tailored frock coat, mostly likely of cadet grey, with padded (quilted) breasts segments that give it that popular military appearance of a smooth even front. You can tell by how smooth the front is and the "puffy" appearance the opening on button side shows

The young gentleman is most likely Infantry. In the larger available image you can see that the gold/yellow does not fill the whole collar as if it was an actual branch collar color. Many militia units utilized what is commonly refered to as false button hole gold lace trim on both sides of the collar. Frequently also seen with a single button. In the larger image you can also see the slight ripples in the gold lace.

This gentleman is actually a Private. The item on the shoulders is acually a strip of gold lace. It would only be sewn onto the coat on the front and back edge. It was both decorative as well as functional. When the full dress eppalettes were worn they slid up under this lace and attached close to the collar with a hook or button/screw device. The lace strip remained there and when the eppallette were worn it held it in its proper place amd position on the shoulder.

Several pre-war companies of the 1st Virginia Volunteers wore dress frock coats very close to this one as well as some others that ended up in the 21st and 23rd Va Infantry amongst others

Frederick