Vintage 1870's S&G safe lock question

[bingobob1955]

I recently purchased a vintage safe with an S&G 1870's lock. Fortunately the safe was open but locked. Having read how to determine the combination by observing the wheels I can open the lock but I'm confused why it opens with only two numbers? Of the three wheels the second and third align together when dialing in the second number. My question is has this lock been changed to open with only two numbers or is there possibly a problem with the lock?
I'll try to post photo's.

[Safecrackin Sammy]

Entirely possible it was changed to open on just two numbers.

Do you know if the lock is a hand change or key change?

[bingobob1955]

It has a change key port. I have tried it numerous times with success but I'm hesitant to lock the door shut before knowing for sure it will open again.

[Safecrackin Sammy]

The only way to know for sure would be to service the lock. Disassemble, clean, inspect, lube, etc.

If its an 1870's lock who knows when the last time was it was serviced.

[bingobob1955]

I would like to do that as I want to paint the safe and have the dial and lock lever re-plated but I don't know the disassembly procedure and don't know if there's even something like that available.

[Safecrackin Sammy]

Should be some general videos on line but it may not apply to your particular lock.

Might be best to have a tech come in and service it. Call a couple of local shops and see what they charge.

Safe locks are always easier to fix when the door is open.

[bingobob1955]

Thanks Sammy, I'll call a few folks and get an idea what they charge. Better safe than sorry.
Regards,
Bingo