I take it that includes burning all of the 40+ roms? Honestly, it sounds about right. It takes literally hours to burn them, and then there's the cost of the chips.Update: the dream is on hold. I was quoted £250ish for the whole work. I then asked about just converting the security board, and I'm still waiting for a response.
If you're interested in doing the leg work yourself, invest in an eprom programmer. You need one that can do 42 pin chips. There's a thread for programmers here:
Best, low cost, programmer for most arcade hobbyists to have???
Then just start burning the mame set for the game. The game will boot without a security board. When you're at that point and you have "working game" you can ask either for a converted security board or decrypted program roms (just four chips).