Can I find out the Cypress (Infineon) FW version number from a Sterling-LWB, -LWB5 or -LWB5+ software release?

Yes. On a Linux PC you can use he command "strings" on the Wifi firmware file you are using and grep for "Version":

strings brcmfmac4373-usb-sa-prod.bin | grep Version

4373a0-roml/usb-ag-p2p-mchan-wfds-idsup-idauth-wowlpf-pktfilter-swdivenhanced-aoe-mfp-clm_min-sr-txbf-proptxstatus-sae-2040coex-bdcsr-msgtrace-sharedotp (config_usb_release_sharedotp) Version: 13.10.246.247 (fb87df5 CY) CRC: 42b20d6 Date: Sun 2020-12-20 19:47:27 PST Ucode Ver: 1192.0 FWID 01-c041ac2e