"The Regency in Great Britain was a period when King George III was deemed unfit to rule and his son ruled as his proxy as Prince Regent. On the death of George III in 1820, the Prince Regent became George IV. The term Regency (or Regency era) can refer to various stretches of time; some are longer than the decade of the formal Regency which lasted from 1811–1820. The period 1795 to 1837, which includes the latter part of the reign of George III and the reigns of his sons George IV and William IV, is often attributed as the Regency era characterised by distinctive trends in British architecture, literature, fashions, politics, and culture. The Regency era ended in 1837 when Queen Victoria succeeded William IV." (Wikipedia)
The statement overall means that the writer's shoes might have been worn by a fop (very fashionable person, one who pursues fashion rather than other goals) during this period, or an officer of Parliament (who wears a traditional uniform similar to what people wore centuries ago). The sarcasm suggests that he or she doesn't think they're suitable for today (or whenever this was written).