Yes, with caveats. In order to print on both sides of a sheet of paper, the paper needs to be thick enough to handle an impression and to not have that impression show through the opposite side of the paper–otherwise, legibility is compromised… and it can look sloppy. While there are a few commercially-available papers that meet this requirement, the best way to assure a good letterpress impression without a hint of that impression showing through is to duplex, or laminate, papers after printing.