At risk of compromising your relief slightly, from what I understand the lead measurements may change depending on the water chemistry flowing through the pipes

At risk of compromising your relief slightly, from what I understand the lead measurements may change depending on the water chemistry flowing through the pipes (i.e. the lead may stay put wherever it is in the system but leech if the right water chemistry (which may still be within regulations) flows through). House pipes being changed is probably 90% of the worry anyway. If it was recently enough, you might be able to pull the original permits and get a better idea of what was replaced.