The ALR Server is completely stock. To understand why they did it let's go back with a little bit of history.
When Pentium II was launched, Intel didn't had the 440LX chipset released. This made for the earlier Pentium II Klamath cpu's to be initially used on motherboards equipped with the 'aging' Intel 440FX Natoma chipset designed for the Pentium Pro.
But, the Pentium II Klamath had a drawback at his launch. It's originally tag ram chip which give the maximum amount of RAM to be cached, only allows for 512 MB to be cached. Moreover, it could be used on only dual cpu systems.
For server side, where more ram must be used and multiple cpu's, Pentium PRO still was the king. Pentium PRO design allowed 4 cpu's but a few, like HP and ALR, managed to use 6 cpu's on one server (see ALR Revolution 6x6). Maximum accessible ram was 64 GB, but the server's was configured for 4 GB.
Because of that, servers with Pentium PRO processors was still launched until the Pentium II Klamath with 2× 72-bit ECC L2 cache for entry-level servers and Pentium II Xeon (it used a different type of slot, Slot 2) was launched and of course their supported mainboards.
Let's go back to this ALR Server. It was meant to be used as a departmental or Workstation server.
For this, slot 1 was used, and the cpu options was of course earlier Pentium II chip's. For chipset's, the only options was P PRO chipset, 440 FX. Because of early issues with P II tag ram chip, the maximum amount of ECC EDO 128 pin RAM modules was set to max 512 MB (4 ram slots). It's very close to SDRAM in appearance but the ram chips are EDO ECC, not SDRAM (see below picture)
Because the Pentium PRO used the same bus as Pentium II, for entry level option, they equipped this system with Pentium PRO because on those times it was a very large available stock's of P Pro's.
For P PRO to be used on slot 1, an adapter must be used, called slotket.
You can also see slotket's for socket370 too (Pentium II Celeron, Pentium III socket370 to slot 1).
Socket 8 slotket adapter was first of his kind and it was created to allow the use of Socket 8 Pentium Pro processors on Slot 1 motherboards.
There was a few manufacturers of those slotket's, like: Tyan, Asus, Intergraph and as you may see ALR.
From my opinion this is the beauty of this server, slotket's. It's very rare and hard to find.
LE: and yes, it can be configured with Pentium II Klamath. I managed to use a 233 pair but to be honest, I love the slotket's appearance and of course, I want to keep it stock. The last but not least, I love the way Pentium Pro look's (see below)