Though in essence gas lanterns in good condition are simple things to light, keep and maintain, given it's age and unknown history, I would exercise some caution before thinking to attempt to light it. Caution of which would include discovering all I could about it, or the type it is to include finding maintenance instructions if there are any around and carrying out that maintenance. as age tends to do bad things to rubber seals of which gas lanterns tend to have.
And if I could not find any specific maintenance instructions I would take to youtube to watch what videos I could find pertaining to gas lanterns perhaps using the search term 'camping gaz' as they are the most popular, and/or consulting someone that knows about gas lanterns in person so they can take you through what needs to be done - try the local scout group as it was in scouts that I personally learned about gas lanterns and pressurised paraffin Tilley lamps.