by "replica" you mean emulator or something else?
replica / new hardware that looks the same, with lights and buttons. Behind the panel is (from the one I looked at) an Arduino running an emulator. Don't know if the blinking lights respond the same or if the hardware switches, ports, etc work.
They do appear to mean emulator.
The PDP-8 was hardware replicated many times. In the '80s it was a common final year project. There's a classic textbook that works through designing and implementing a clone of the PDP-8/I [1]. I've run into a number of threads over the years where hobbyists have done it with TTL to varying degrees of completeness.
The Apollo Guidance Computer was recreated by a hobbyist from the original designs using a modern logic family but gate-equivalent -- and I can't find it online anymore! Anyone know?
You can still build an original Apple II. [2] Being from the late 1970s there was no custom logic; it's straight TTL plus a 6502, and all the chips are still in production except for the ROMs and DRAM, which are easy enough to work around or find used.
[1] https://www.amazon.ca/Art-Digital-Design-Introduction-Top-Do...
[2] https://www.reactivemicro.com/product/apple-ii-plus-rev-7-rf...