Although my bike is a CB500, I'd like to share my experience. On the CB500 you'll find a similar T-joint with two O-rings on either side. Maybe my bike is an exception, but on mine the O-rings still seal well after 40 years. Last year I had to replace the fuellines and those of you that have done this chore, know what a struggle it is to get the fuellines over the nipples of the T-joints. I had lost my temper and was really using violence to get them on. I was almost sure I had damaged the O-rings on T-joints in the process and that it (finally) would be my turn to replace them. With little hope I opened the petcock. Guess what, nothing leaked, nothing. You should have seen how wild I had moved the T-joints back-and-forth. Unbelievable. Honda did well by putting two O-rings on either side. So you may consider just to keep what you've got. You can simply test if they still seal and leave them where they are.
