I think I found answer myself. wAP LR8 shares hardware with wAP R (https://i.mt.lv/cdn/product_files/guide_wapr_180505.pdf). SIM slot is used by miniPCIe LTE card that is inserted into the slot. In case of wAP LR8 and wAP LR9 miniPCIe slot is occupied by R11e-LR8/R11e-LR9 card.
Exactly, If you replace LoRA module for a compatible UMTS/LTE module, it should works with SIM card inserted and the device properly configured. If you want an outdoor device that support LTE and LoRA at same time, LtAP (Not mini version) should be works.