Yes — for a standard hot-shoe flash, manual triggering is typically done by briefly shorting the center contact on the foot to the metal shoe rails/ground. That’s the basic ISO hot-shoe trigger method used by most flashes. On more advanced flashes, extra pins may handle brand-specific features, but the center pin plus ground is usually the basic manual trigger.

If your flash has a separate two-wire lead, it may be an alternate sync connection; without seeing it, that’s hard to confirm.

Important caution: older flashes can have high trigger voltages, so don’t connect an unknown vintage flash directly to a modern camera, radio trigger, or other electronics unless its trigger voltage is known to be safe. If the flash is corroded or water-damaged, it’s best not to use it.