When I moved into my current house in 2003, it still had a bt rottary phone. the drop wire came down from the pole outside, through a bakerlite GPO Block Terminal No 20/4 then to the telephone.
The BT engineer at the time said it's an old line, but it works so BT isn't going to change it. The line is around 1600m in length to the exchange according to the attenuation, and none of it is twisted. I'm not having any connection/noise problems at all. I have maximum sync and a stable connection.
Unless your having a problem, I wouldn't worry about it.