The thing being metal has a very tiny impact on being more likely to be struck by lightning. There is no such thing as "attracting" lightning. Lightning starts as a widespread charge in the clouds, until it reaches a tipping point and discharges. Often this discharge is between two parts of the same system in the sky. However sometimes the discharge can be with the ground itself.
When the electric field is large enough, a similar field is induced in the ground. These fields are often on the large side, with one pair of fields being able to serve a lot of strikes and each strike being a whole bunch of discharges. At the top the air begins to break down and form a lightning channel. This follows a random, often branching pattern, moving generally downward being attracted by the field in the ground. When this channel gets close to the ground little "feelers" begin to discharge from sharp edges of everything near the channel. Once one of these feelers touches the lightning channel, the actual strike happens. That single channel will be used to transfer energy, due to the difference in field charge. The air becomes super heated and turns into a hot plasma. We see the bright white lighting arc and a wave of expanding air moves out from the strike. Often these strikes pulsate, where the channel moves a lot of energy, heats up, stops moving energy, cool down and heat up again. I'm not sure how many cycles one strike has, I think something around a dozen or so. Sometimes when there's multiple suitable channels available, it will jump around between these, which can look very pretty.
As I said these fields are usually on the big side and that's what determines where abouts the strike will occur. The bit on the ground only plays a part in the last few meters of a process that is often hundreds of meters long. The material doesn't matter all that much, as the charge is enough to break down the air itself. If something has sharp edges often matters more than the material, but the biggest factor is height.
Large towers, a singular tree in a field and stuff like that is said to "attract" lightning, because we dumb monkeys see those things get hit more often than elsewhere (but not exclusively so). Like I said the lightning channel is formed up to down, because of the two opposing fields. When the channel gets close to something, it can complete the channel. So things being more up are more likely to do so, just by virtue of being up.
Just a little tangent not directly related to your question tho. If you want to ground the thing to make it less likely to explode when hit by lightning, sure go ahead. But remember a lighting strike is very violent, so it will never be safe. Best to stay indoors during a heavy lightning storm.