I have a couple of STR8S in that condition (bought like that: I had to buy 7 for 12 Euros just to get a John Barber in great conditions), they are great below the nose and to get perfect mustaches. I think in the past it was quite common to regrind razors to keep on using them, and so the spine is usually thin in similar pieces. I have only one blade that has not been reground properly, but it is not a problem for shaving: I just have to hone it more often then the others. The spine wear area is getting larger and larger, I guess I'll get a mini-wedge sooner or later