I'd say if they are the older style , "Tin can " fittings with a replaceable lamp then you can .
Unless they're really old fittings with big energy guzzling lamps in them ....they will have either a 12Volt lamp witch has two spikes to connect to the holder or a mains voltt lamp GU10 with two mushrooms as caps .
Both lampholders can be replaced ( 12Volt ones often fail , usually the flex)