I purcahsed mine from Automotive Tools and Supplies in the UK
Auto-tools subframe alignment pins . The cost was 28.70 pounds or about $46 with another $16.80 for shipping from UK to Virginia, US (About $63 total). Shipping took several weeks so if you need them plan well ahead. (note that there is more involved with these tools than just steel "pins")
For some reason no US based tool supplier offers these pins (and I certainly looked!) so you will almost certainly have to purchase from overseas.
I don't know if you really need these to re-install subframes - I am just a stubborn SOB when it comes to doing auto repairs by the book. It does seem to me that it is so much work to do this type of job that it was worth the money to assure they are "factory" aligned.
You could also just spray paint around the mounting points before removal and use the spray pattern to ensure you have returned alignment during installation. Would work assuming alignment was OK to start with.