con rod nuts

I noticed that the nuts i took off my con rods look like the ERC1029 part in my parts manual i.e. a nut with a nyloc-looking head.
I was therefore thinking i ought to replace these with new ones - but when i look on the web ERC1029 has been superseded by ETC5155, which looks like a nut with no nyloc head.
I had a look in the series 3 workshop manual and all it talks about is ensuring they are torqued up (to a 25 or 35 lbf ft).

So
1) should i replace my existing nuts
2) if so, what should i use.
And what stops these nuts getting loose and destroying my newly re-bored engine.

This is what I used from pa blanchard
The manual says use NEW nuts. Torque them up right shouldn’t come loose

new nuts on order. many thanks for advice