Go email Huw Finney of Photo.net. He would know because I found out about R2 RF adjustment from his website.
Alternatively, you can disassemble your R2 to find out yourself. That makes a really good excuse to buy future R3 since you've promised your boss, eh I meant wife, not to buy anymore Voigtländer products with your PII bwahahahahahahaha *evil*
Just joking Peter