According to https://collections.arolsen-archives.org/de/document/6160434 375 is the correct number.
For the description „Ohrdr. Blech“ I selected Ohrdruf in the menu, could also have selected Blech.
Edit: after reading [Nummern-Namen-Kartei Männer Buchenwald - Part 12] 9754248 I added both „Ohrdruf“ and „Blech“ with prisoner number 1375
Question: I could not find any information about a subcamp called „Blech“. Was it a codename or part of Ohrdruf camp?