a4x2 sim-sp reporting wrong type for some targets

On a4x2:

root@oxz_switch:~# omdb mgs inventory
note: MGS URL not specified.  Will pick one from DNS.
note: using DNS server for subnet fd00:1122:3344::/48
note: (if this is not right, use --dns-server to specify an alternate DNS server)
note: using MGS URL http://[fd00:1122:3344:101::2]:12225
ALL CONFIGURED SPs

    TYPE   SLOT 
    Sled   0    
    Sled   1    
    Sled   2    
    Sled   3    
    Switch 0    

SPs FOUND THROUGH IGNITION

    TYPE   SLOT SYSTEM_TYPE 
    Sled   0    Gimlet      
    Sled   1    Gimlet      
    Sled   2    Gimlet      
    Sled   3    Sidecar     
    Switch 0    Gimlet      

...

In ignition, switch 0 reports itself as a Gimlet and sled 3 reports itself as a Sidecar. That seems wrong? I confirmed this is wrong in the MGS response:

$ curl -s http://[::1]:12225/ignition
...
(piped to jq off-box)
[
  {
    "id": {
      "type": "sled",
      "slot": 3
    },
    "details": {
      "present": "yes",
      "id": {
        "system_type": "sidecar"
      },
      "power": true,
      "ctrl_detect_0": true,
      "ctrl_detect_1": false,
      "flt_a3": false,
      "flt_a2": false,
      "flt_rot": false,
      "flt_sp": false
    }
  },
  {
    "id": {
      "type": "switch",
      "slot": 0
    },
    "details": {
      "present": "yes",
      "id": {
        "system_type": "gimlet"
      },
      "power": true,
      "ctrl_detect_0": true,
      "ctrl_detect_1": false,
      "flt_a3": false,
      "flt_a2": false,
      "flt_rot": false,
      "flt_sp": false
    }
  },
  {
    "id": {
      "type": "sled",
      "slot": 0
    },
    "details": {
      "present": "yes",
      "id": {
        "system_type": "gimlet"
      },
      "power": true,
      "ctrl_detect_0": true,
      "ctrl_detect_1": false,
      "flt_a3": false,
      "flt_a2": false,
      "flt_rot": false,
      "flt_sp": false
    }
  },
  {
    "id": {
      "type": "sled",
      "slot": 1
    },
    "details": {
      "present": "yes",
      "id": {
        "system_type": "gimlet"
      },
      "power": true,
      "ctrl_detect_0": true,
      "ctrl_detect_1": false,
      "flt_a3": false,
      "flt_a2": false,
      "flt_rot": false,
      "flt_sp": false
    }
  },
  {
    "id": {
      "type": "sled",
      "slot": 2
    },
    "details": {
      "present": "yes",
      "id": {
        "system_type": "gimlet"
      },
      "power": true,
      "ctrl_detect_0": true,
      "ctrl_detect_1": false,
      "flt_a3": false,
      "flt_a2": false,
      "flt_rot": false,
      "flt_sp": false
    }
  }
]

I spent some time trying to track this down but it wasn't obvious. The initial ignition states appear to be set here in sp-sim:
https://github.com/oxidecomputer/omicron/blob/903b9929e3add74c9407274f2315fdff45126d2e/sp-sim/src/sidecar.rs#L1275-L1280

Start in sp-sim/src/sidecar.rs at the initial ignition-state setup around lines 1275-1280, then compare those states with the /ignition MGS response and omdb mgs inventory output shown here. Done means switch 0 and sled 3 report their correct system types instead of Gimlet and Sidecar respectively.