Yes nothing special about this days and all Hadiths are fabricated (موضوع).
At the IslamQA They answer that
Ibn Baz said
Celebrating the night of the fifteenth of Sha’baan (Laylat al-Nusf min
Sha’baan) by praying etc, or singling out this day for fasting, is a
reprehensible bid’ah (innovation) according to the majority of
scholars, and there is no basis for this in sharee’ah.
And they answer another question about that and said
There is no saheeh marfoo’ report that speaks of the virtue of the
middle of Sha’baan that may be followed, not even in the chapters on
al-Fadaa’il (chapters on virtues in books of hadeeth etc.). Some
maqtoo’ reports (reports whose isnaads do not go back further than the
Taabi’een) have been narrated from some of the Taabi’een, and there
are some ahaadeeth, the best of which are mawdoo’ (fabricated) or
da’eef jiddan (very weak). These reports became very well known in
some countries which were overwhelmed by ignorance; these reports
suggest that people’s lifespans are written on that day or that it is
decided on that day who is to die in the coming year. On this basis,
it is not prescribed to spend this night in prayer or to fast on this
day, or to single it out for certain acts of worship. One should not
be deceived by the large numbers of ignorant people who do these
things. And Allaah knows best.
And about weak ahaadeeth if we must take it or no, The scholars differed concerning acting upon weak ahaadeeth, Some scholar said it's ok to acting upon it with some conditions and some said forbidden that.
You can see this answer about it
Al-Haafiz ibn Hajar (may Allaah have mercy on him) summed up the
conditions for weak ahaadeeth
1 – It should not be very weak, and one should not act upon a hadeeth
which was narrated only by one of the liars or those who are accused
of lying, or whose mistakes are serious.
2 – It should mention a good deed for which there is a basis in
3 – When acting upon it one should not believe that the action is
well-founded, rather he should do it on the basis of erring on the
side of caution.
And what i know you concerning acting upon weak ahaadeeth after condition above, Weak ahaadeeth must not conflicts with ahaadeeth Saheha you must do what ahaadeeth Saheha said.
God bless you