On the surface, probably not.
While a comment noted that an impact large enough to "fragment" a planet will behave more like a "splat", the implications of this have largely been missed. Such an impact will produce an enormous cloud of ejecta (a significant fraction of the planetary mass) which will mostly fall back to the surface. This will have two effects.
First, the impacts will produce an enormous amount of heat, and a lot of the impact areas will become molten, erasing any signs of man-made artifacts.
Second, even a small fraction of the planet's mass will bury the remnant surface very deep. For instance, assuming uniform density, 1% of the earth's mass will produce a blanket about 13 miles deep. Given the scale of the ejection event, a fairly uniform coverage should be assumed.
As a result, any visiting aliens had better be interested in relatively deep (much deeper than we can do) exploration of the pathetic remnant of a once-living planet. Exposure of core material at high temperature will have locked up all the atmospheric oxygen, and for quite some time the surface temperatures will be high enough to keep the water as vapor (that is, steam).
Of course, you may have noticed a possible loophole in the opening sentence of this answer. The ejecta will not entirely return to the surface, and for a shorter or longer period some of it will orbit the earth - we'd probably have a very nice set of rings for a few millenia - and if the visitors are lucky they might encounter artifacts in orbit. The odds on this are not great, but I don't see how they would be zero, either. You'd expect to see fragments of refined metal, and small, dense objects might survive the ejection process in a recognizable form. This might apply to objects such as steel tools and jewelry. Platinum, for instance, is quite hard, strong, and melts at very high temperatures.
EDIT Even a badly damaged Rolex would be a pretty sure sign that someone had been on the planet.
Unless, of course, the Blind Watchmaker debate is universal. END EDIT