I mean...maybe? But with Dooku and Grievous dead, I don't know that there's any actual evidence connecting Palpatine and Sidious. I can certainly see Tarkin arguing the reverse, even assuming the surrendering Separatist leaders decide to try to out someone they can't identify, but were actively terrified of (so much so that one of them famously didn't give up his existence despite being arrested and on trial).
Because after all, do they know that they have someone high up in the Senate or someone high up in the Republic? Like, say, a Jedi Master and general? After all, who better to have been Dooku's secret ally then, say, an old companion and ally like Mace Windu?
Now, the midichlorian count is an interesting point. First, I'm not actually sure you can test a dead person for them? I don't know how they work, but, given the nature of the Force, it seems entirely possible to me that they die with their 'host'. Assuming they don't, there's two major questions:
1) Does anyone who's not a Jedi know about them? They don't seem to be widely known or tested for. If not, then the obvious answer to 'look at his midichlorian count, he had to be a Force Sensitive' is...'well, isn't that very convenient that you have this unknown test to identify such people that only came up after you assassinated the Chancellor?'
2) Does a high midichlorian count mean you're impossible to hide without skilled action, or does it just mean that if you get appropriate training, you can be a more powerful Jedi/Sith? It's not like everyone instantly knew Anakin was super-powerful, though Qui-Gon figures it out. Again, I see a very likely response of 'I'm sure he had the potential to be a great Jedi and may even have instinctively used the Force somewhat, I bet if you test the Senate, you'll find a lot of elevated counts! They're the most successful politicians on their planet/sector! Being convincing, understanding the motives/intentions/plans and attempting to predict outcomes are all things that they try to do and being Force Sensitive helps with all of them!'