This is fun question! I would say that the answer to your question is: not exactly. Before we get into why this is so, let's talk a little bit about what ice cream is and how it melts.

Ice cream is an emulsion (a mixture) of two substances that don't normally mix with one another: fat and a sugar/water solution. Fats are a type of molecule called lipids, which typically don't mix with water. But in ice cream, fat particles are dispersed with water, sugar, and air.

Now, the amount of sugar and air are probably the most important factors in determining how fast the ice cream will melt. Sugar is important because it is a solute in the water -- this means that molecules of water surround the sugar molecules in the solution. Sugar and other solute molecules have the effect of lowering the freezing temperature of a solution. This is called "freezing point depression." Now, freezing is a process by which liquids transition into solids. The opposite process, where solids transition into liquids is called melting. The freezing point of a substance (temperature at which it freezes) is the same as the melting point (temperature at which it melts) Thus, if the freezing point is being lowered, so is the melting point. That means that ice cream with more sugar in it will melt at a lower temperature than ice cream with less sugar in it. In turn, because the more sugary ice cream has a lower melting temperature, it will also melt faster at room temperature than the less sugary ice cream.

The other factor we said is important is how much air is in the ice cream. Ice cream usually has little pockets of air throughout. Ice creams that have more numerous and smaller pockets of air have higher surface area to volume ratios. Higher surface area means that the ice cream will melt faster.

So ultimately, the answer to your question really is, it depends on what's in the ice cream. The amount of air and sugar in the flavors plays a large role in how quickly the ice cream will melt. Additionally, more exotic flavors with other substances in them will melt differently as well (things like Rocky Road and Pistachio). I hope this helps!