I would say, try a sample first of yellow builders sand with white cement, snowcrete and lime.
A lot will depend on the sand and ratios mixed at, best to try a few samples and see what it drys out like, then adapt to suit.
Failing that you can get a lime mortar colour matched by the suppliers, ie Trad-Lime.

you need to gauge the mortar precisly .the gauge is 6 shovels of soft sand 1shovel of lime and 1of cement.the shovel needs to be full up with the same amounts of each ingrededient.

If it was built in the 1800's it will be lime mortar and not cement....you need some lime putty, hydraulic lime (not hydrated) and a mix of sharp and soft sand...it will tell you the mix ratios on the back of the lime bag...3-1 if I remember correctly, I always add a trowel full of lime putty to plasticise it. Make sure you wear protective clothing and especially eye protection....especially with the lime putty!!,if you were to put your foot in a tub overnight by the morning all that will remain will be bone..be warned.