I used a press-fit DIN connector a number of years ago, and had to acquire a tool/fixture from the connector mfr. for pressing it into the board. It was quite expensive, as I recall, but depending on how many boards you're making, it might not matter. I was only making a few and was able to get the local rep lend me the tool. You could probably make your own, depending on time/cost etc. When you layout the board, you may have to allow some clearance for the tool; hopefully the connector mfr will give you this info.
I think it might be up to the board assembler to decide at what point they want to install the connector.