Items in ladyparts.ic (BigDaddyHurt’s shop) is entirely RNG-based.
If you are not seeing specific parts (such as Hypercamo Limbs), it simply comes down to luck, and you may need to check back over time.
About VolksAuto limbs:
VolksAuto parts cannot be purchased from the shop.
They are obtained through Company Contracts and Streaming, not through normal shop rotation.
About the Stock Market system:
The Stock Market is purely based on RNG.
There is no fixed pattern; it is randomized.