I have a gardall safe that was given to me with no key need to know how to unlock it?

i did some moving for a woman and she gave me two safes that she no longer had the keys or the combinations to. she said i could have it and sell for scrap metal or keep or whatever. its a really nice safe and i want to keep it but i am wondering what to do to get it open. i talked to a locksmith who said that i would have to have the factory key and the default combination for that model but if the combination had been changed that i wouldnt be able to get into it. i am thinking he is just trying to make money off of me. it has a combination dial and also a place for a key. do these safes require the combination and the key or can i just get a key and open it? i have went online and believe i can order a key for it and he said he could order a key for it for me no problem. just need to know if i really need the combination and the key or do i just need the key to open it? here are the numbers on the safe s-414724 and it has a2312 on the lock. please let me know because this is an expensive safe and i really need it for my home....