Was Britain's Home Guard unique in having veteran members?

Was the British Home Guard unusual because other countries lacked First World War veterans?

No. Other countries had veterans too; Britain's island position gave its defenders more time to organize and prepare.

Other countries also had veterans available for local defence. Britain's distinctive advantage in this comparison was the time afforded by its island position. That interval allowed formations to organize, train, and receive replacement equipment before a possible invasion. Veteran membership alone therefore does not explain the assessment of British readiness.